Flooding process for recovering oil from subterranean oil-bearing strata



UNITED STATES- PATENT OFFICE FLOODING PROCESS. FOR RECOVERING 01L FROMSUBTERRANEAN OIL-BEARING STRATA Melvin De Groote, UniversityCity, andBernhard Keiser, Webster Groves, Mo.,

assignors to Petrolite Corporation, Ltd., Wilmington, Del., acorporation of Delaware No Drawing. Application March 6, 1940.

Serial No. 322,534

10 Claims. (c1. 166-21) This invention rel-ates to the recovery of oilfrom subterranean oil sands and oil-bearing strata, and has for its mainobject to provide a practicable, inexpensive flooding prOCSSS for re- 5covering oil that is held by adsorption, absorption, or in someequivalent manner, on subterranean oil-bearing strata, such as, forexample, the oil sands or. oil-bearing strata of exhausted oil fields,or the oil sands or oil-bearing strata of .oil flelds that have beentested and abandoned because they did not contain a sufficient quantityof oil to make it feasible .to attempt to recover the oil byconventional oil-producing procedure.

Briefly described, our process consists in introducing water with whicha treating agent or addition agent is mixed to form an aqueous treatingsolution, into a number of oil wells located in an exhausted orabandoned oilfield, and permitting said treating solution to travelthrough-the sub- 29 terranean oil sands or oil-bearing strata and riseto the surface of the ground through a predetermined opening. Thetreating solution or aqueous vehicle employed asthe flooding medium,operates to liberate the film or coating of oil on the 25 particles ofthe oleiferous structure, and then flush the oil off said particles andcarry the oil upwardly to the surface of the ground.

Oil exists in oil sands or similar strata in two" different states, :1.e., as free oil, that is located 30 between the voids of the sands, andas fixed oil,"

which is held by adsorption (and perhaps to some degree-by absorption)on the particles of sand, and which is commonly referred to as the filmof oil that adheres to the particles'of sand or to the 35 particles ofthe oleiferous structure. Such fixed oil may be said to be held bysorption."

Free oil can be recovered by conventional methods of oil producing, suchas draining the oil in conjunction with liquid or gaseous pressure, and

40 creating an artificial fluid or gaseous pressure in the sand bed, soas to dislodge the oil from the sand bed and thereafter conduct thedislodged oil to the surface of'the ground by any suitable meansormethod. Fixed oil, i. e., the coating or 45 film of oil on the sand ororganized strata, cannot be recovered by any of the conventional.

methods or means used to produce oil, because it is held as -a filmsurrounding the grain of sand duction by conventional methods, it is notalways desirable to use old oil wells for either the purpose ofintroducing the aqueous vehicle into the subterranean oil sands oroil-bearing strata, or for I expulsion of the oil or the fluid with itsoil content 5 in loose admixture or emulsion. In some in-- stances theentire operation is carried out by means of wells drilled specificallyfor the purpose of flooding the formation in accordance with apredetermined plan. Sometimes the operation is 10 conducted in part bymeans of some of the old existing wells, and in ,part by means of somenew wells drilled in accordance with a predetermined arrangement. Theabove described procedure, which is commonly referred to as the floodingI5 process, has been employed successfully'in numerous fields, includingcertain fields in Pennsylvania, certain fields in northern Oklahoma,certain fields in southeastern Kansas, and elsewhere.

Attention is directed to the'bibliography pf water-flooding whichappears in "Petroleum Prpduction, by Cloud, University of OklahomaPress, 1937, page 435. See also U. S. Patent No. 1,826,371, datedOctober 6, 1931, to Spindler.

It is not necessary to-indicate all the advantages to be obtained by theaddition of a suitable chemical compound or treating agent to water, soas to produce an aqueous treating solution that is intended to be usedinstead of ordinarywater, which may, in essence, represent a dilutebrine containing usually appreciable amounts of soluble calcium andmagnesium salts. Such a. treating solution, if properlyprepared,constitutes an aqueous vehicle which hasv at least an apparentpreferential wetting efiect for the sand or strata, and thus loosens orremoves the oil which might not be removed by water alone. Said aqueousvehicle also has the characteristic of tending to prevent the formationof emulsions as said aqueous vehicle and the liberated oil travelthrough the 40 sand or strata and through the various conduits used inthe procedure. It probably has the effect of decreasing the apparentviscosity of water;or to state the matter in another way, the aqueousvehicle or treating solution probably permeates sands and variousoil-containing strata which might not be permeated at all by wateralone, or at least, under conditions of diminished pressure. There arenumerous other advantages not'necessary to mentionfwhich resuit from theuse of an aqueous vehicle or treatme solution of the kind abovementioned.

In actual practice, it is found that very few chemical compounds areactually of value as addition agents to the water employed in recoveringalthough there are available thousands of wetting agents and perhapshundreds of demulslfying agents, very few have the desired property ofbeing suitably resistant to the soluble calcium and magnesium salts,which are either invariably present in the Water used for flooding thesubterranean sands or strata, or liable to come in contact with saidwater and contaminate the same. Some wetting agents and demulsifyingagents, although stable in the ordinary sense, are not stable for thepurposes of flooding. Sometimes, six to eighteen months may pass beforethe flood water re-appears atthe surface, carrying the recovered oil.Accordingly, it is necessary that the addition agent must be stableforsuch a period of time; and furthermore, since the same flooding wateris used over again, it is necessary that the addition agent mustcontinue to be stable almost. indefinitely. Furthermore, there arechemical compounds which meet the test of stability; but they do notsufllciently lower'the surface tension of the aqueous vehicle within thelimits 01 possible economic use. Then too, although some chemicalcompoundsmay lower thesurface tension, and may be feasible economically,they are not employed for the reason that they do not show otherdesirable properties, as, for instance,

apparent preferential wetting effect, etc. Some chemical compounds whichappear stable under ordinary conditions, even'when allowed to stand fora long period of time, for instance, eighteen months, decompose readilyunder conditions of use, where they are subjected to pressures such asare required in the ordinary course of forcing the aqueous fluid throughthe sands or strata. Some addition agents are objectionable apparentlyfor the reason that they build up deposits on the strata, which greatlydecreases the speed offlooding, and perhaps in some ways, produceresults which are inferior to those which are obtainable by the use ofwater alone, It has been suggested that this objectionablecharacteristic is related to excessive preferential wetting effect, butthis is purely a matter of speculation, al-' though the assumption maybe correct.

We have found that a very desirable agent for addition to the water usedin flooding procedure (the said water usually consisting of a dilutebrine), is a glycol or polyglycol ether of the type obtainable bycausing an aromatic or hydroaromatic hydroxyl compound substituted inthe nucleus by at least one hydrocarbon radical or the equivalentthereof, containing at least four carvbutylene oxide, or the like.

bon atoms, to'react with an alpha beta alkylene oxide, suchas ethyleneoxide, propylene oxide,

broadly speaking, 'are well known compositions of matter, but it may bedesirable to indicate their method of manufacture in some detail.

One may employ any ofthe procedures here-' inafter described, in order.to obtain glycol or polyglycol ethers from aromatic or hydroaro- Suchcompounds,

, 2,233,381 oil by flooding procedure. One reason is, that waterinsoluble prior to-the introduction of the ether chain.

Addition agents suitable for use in our process, may be obtained bytreating or reacting substituted hydroxy alicyclic compounds of the kinddescribed withalkylene oxides of the type which is characterized by thepresence of a radical indicated by the following structure:

Such compounds may be prepared in such a manner that the alkylene oxideenters the substituted isocyclic hydroxyl compound only once, but

preferably the compounds are prepared in such a manner that the alkyleneoxide enters several times, preferably at least four times.

In a general way, the products obtained, or at least part of them, mayfollowing constitution:

Li. 4.. l

R.o :H- c11 cH0- -H R 5H it: ,JX wherein R stands for the aromatic orhydroaromatic radical, which is substituted by at least one hydrocarbonor acyl radical containing at be exemplified by the least four carbonatoms, and the radical R may also be further substituted. As previouslyindicated, the carbon atom chain in either the hydrocarbon radical orthe acyl radical, may be interrupted by an oxygen atom, or an oxygenatom may serve as aside chain carbon atom-nuclear carbon atom link. R1and R2 stand for hydrogen or aliphatic radicals, which may besubstituted by OH or Cl; and X stands for a whole number from 1-100, butusually and preferably, from 3 or 4 to 40. Compounds of the secondgeneral formula may possibly be formed when an alkylene oxide, such asglycidol is employed. It is understood thatall reference to alkyleneoxide or its functional equivalent is intended to mean the type ofalkylene oxide commonly referred to as in alpha beta alkylene oxide, i.e., where an oxygen atom represents a linkage between-two adjacentcarbon atoms, although the oxygen linkage does not necessarily involve aterminal carbon atom; and any functional equivalents are intended toinclude this same characteristic structure in an equivalent manner. 7

'Aswill be subsequently pointed out, a wide variety of alkylene oxidesmay be employed, and also equivalents such as glycidol, epichlorhydrin,

various chlorhydrins, etc. Furthermore, it is quite possible that thestructure of the. polymerized' alkylene oxide chain or its equivalent,at

least insome instances, is not as simple as indicated by the aboveformulas. This is based -on the well known properties of polyethyleneoxide and related compounds, and particularly,

polymerization products derived from ethylene Reference is oxide. undervarious conditions. made to Chemistry of Synthetic Resins,-by Ellis,1935, chapter 50, and to U. S. Patent No. 1,921,378,

dated August a, .1933, to Webel, and 5. Patent 1 No. 1,976,628, datedOctober 9, 1934, to Wittwer. For this reason the previous structuralformulas are submitted primarily to show the point of introduction ofthe polymerized ether radical or its equivalent, rather than the actualstructure itself, although such formulas may be applicable to a numberof members of the broad genus.

Thus, it would appear best to characterize the products in the heretoappended claims in terms of the method of manufacture, rather thanattempting to rely upon structural formulas, in view of what has beensaid.

An alkylene oxide may be added in the gaseous or liquid phase, to themelt of a substituted water-insoluble isocyclic hydroxyl compound, asdefined above, at a temperature at which the alkylene oxide is absorbedby the hydroxyl compound, and which generally lies between 50? C.

and 250 C. It is also possible to cause the subduring which heating maybe advantageous at the beginning of the reaction. In these reactions thelength of the polyglycol ether chain is determined by the proportion ofthe alkylene oxide caused to react. In any event, the amount employedmust be suiiieient to produce water solubility, but not of suchproportion that surface activity is lost. This particular point will bediscussed in detail subsequently. It is well known that variouscatalysts may be employed for the formation of the ethers andpolyethers; and the particularly desirable catalysts include causticalkalies, alkali alcoholates, tertiary non-hydroxylated organic bases,and the like; and furthermore, in some instances at least acidcompounds,

- in place of the oxides themselves.

such as potassium bisulfate, may be employed. It is also known, ofcourse, that the halohydrins corresponding to the alkylene oxides may beused The previously formed glycol ether chains may also be combined withpolycyclic hydroxyl compounds substituted in the manner indicated, butin any one of various methods, for instance, the following procedure:

The substituted isocyclic hydroxyl compound in the form of its alkalicompound (alcoholate or phenolate) is caused to react with a selectedhalohydrin, so that one obtains a monoglycol ether of the substitutedisocyclic hydroxyl compound. Such derivative is then transformed intothe halogen alkyl ether, for instance; by treatment with thionylchloride; and the halogen alkyl ether of the substituted isocyclichydroxyl compound is caused to react with polymerized alkylene oxide,for instance, a polyglycol derived from ethylene oxide in the presenceof caustic alkali.

As suggested previously, as far as the substituted radical is concerned,carbon-oxygen-carbon linkages may replace carbon-carbon linkages. Asexamples of substituted isocyclic hydroxyl compounds, which may be usedas startingmaterials for the addition agents employed in our process,are the following: Normal butylphenols,

isobutyl-orthoacresols, .di-isobutyl-phenols, isoiso-octylphenols,iso-octyl-orthochlorphenols, nhep tadecyl-para-hydroxyphenylketone ofthe formula C1'IH35CO.CsH4OH, orthoand para-benzylphenol, cyclohexylorthocresols, para oxydiphenyl, para-oxy-phenyl-camphanes, the corre--sponding condensation products of phenol or the cresols, withditerpenes, and the like.

Likewise, one may employ various partially or totally hydrogenatedderivatives of the above. Generally speaking, if the isocyclic nucleuscontains only one nucleus substituent radical (excluding the hydroxylradical), and if such substituent radical contains a tertiary alkylradical, then it is desirable that such alkyl radical contain at least 8carbon atoms. In any event, however,-the hydroxyl compound, prior toetherization, must be water-insoluble.

Besides the compounds mentioned, there may be used various otherisocyclic hydroxyl compounds substituted, as stated above, which areobtained in the form of technical mixtures. The substituted isocyclichydroxyl compounds may be prepared in various ways. For instance,olefinic compounds containing at least four carbon atoms may be causedto react in known manner with aromatic hydroxyl compounds. In this casethere may be used definite olefines, for instance, isobutylene,d-i-isobutylene, normal dodeoylene, cyclohexane, camphene or the like,or the olefinemixtures obtained, for instance, by dehydrating themixtures of primary alcohols having about four to eight carbon atomsproduced in the reduction of carbon monoxide by means of certaincatalysts or by catalytic polymerization by one of the known methods oflow-molecular olefines, such as ethylene, propylene, isobutylene or thelike, or of olefines obtained from the primary alcohols having aboutfour to eight carbon atoms produced in the reduction of carbon monoxide.

Substituted aromatic hydroxyl compounds, suitable for use in producingthe addition agents contemplated by our invention, may also be obtainedby the known condensation of aromatic hydroxyl compounds with alcoholscontaining at least four carbon atoms, for instance, tertiary butylalcohol, alcohols having about four to eight carbon atoms (which; asabove mentioned, are produced in the catalytic reduction of carbonmonoxide), cyclohexanol, methylcyclohexanols or others, includingderivatives of hydrogenated naphthols.

Alkyl substituted aromatic hydroxyl compounds may also be obtained fromacyl-substituted aromatic hydroxyl compounds by reducing in known manneronly the keto group.

The acylaromatic hydroxyl compounds, which may be used as startingmaterials, may be prepared by esterifying the appropriate carboxylicacids or their derivatives with the aromatic hydroxyl compounds and thentreating these esters with aluminum chloride, whereby they undergomolecular rearrangement to the corresponding ketones.

The hydroaromatic hydroxyl compounds substituted in the nucleus by atleast one hydrocarbon radicalQwhich may also be,used as startingmaterials, may easily be obtained according to known methods, forinstance, by the catalytichydrogenation of the corresponding aromatichydroxyl compounds in the presence of a hydrogenation catalyst.

As examples of alkylene oxides or equivalents which are brought intoreaction with the substituted isocyclic hydroxyl-compounds, thefollowing may be mentioned: ethylene oxide, 1:2-propylene oxide, 1:2- or2:3-butylene oxide, butadiene dioxide, cyclohexene oxide, glycidol,epichlorhydrin, beta methyl glycidol, beta methyl epichlorhydrin,isobutylene oxide, or the like.

The glycol and polyglycol ethers of the type referred to are products ofcomparatively recent commercial development; in other words, havingfound application during the last decade. Many are produced in a formthat is water-insoluble or only shows a slight tendency towards watersolubility. In other words, the products so obtained are used as readilyemulsifiable oils, and some will produce a more or less stable emulsionwith water.

Solubilities depend upon the alkylene oxide used and the length of thechain formed in relationship to the orignial water-insoluble parent ma-I terial. It is to be noted, however, that the type employed for thepresent purpose is limited to the water-soluble surface-active type.Such types are readily available from the water-insoluble and partiallywater-soluble type by the introduction of a longer ether chain.Furthermore, it has been found possible to develop certain types ofcompounds which represent distinctly new species. For this reason, itwould appear desirable to indicate the range of suitable material byreference to a number of examples.

Example 1 Iso-octylphenol is treated with approximately b-lO moles ofethylene oxide (or a slightly additional amount, if need be), so as toproduce a water-soluble surface-active iso-octylphenyl polyglycol ether.

Example 2 Isododecylphenol or a closely allied homologue may beemployed. Such materials. can be obtained in various manners, forinstance, by condensing phenol with a mixture of the polymerizationproducts with propylene or propylene-containing gases, which consistmostly of unsaturated hydrocarbons havingtwelve carbon atoms. Similarly,one may treat phenol with isododecylchloride in the presence of aluminumchloride or a catalyst of similar action. Such material, i. e.,dodecylphenol, may be treated in the manner in dicated in Example 1, ormay be treated in the following manner:

To approximately 260 parts of the alkylated phenol (isododecylphenol)there is added one part of sodium methylate. Thereupon ethylene oxide isintroduced at 140460 0., until the increase in weight amounts to 570parts. The isododecylchloride can be prepared in any manner, but is mostsuitably prepared by the monochlorination of the light oil traction,consisting essentially of hydrocarbons having 12 carbon atoms.

Example 3 A kerosene fraction distilling between substantially 160 C.and 245 C. and consisting of paraffinic hydrocarbons, the majorproportion of which is selected from the group consisting of decane,

undecane, dodecanc, and tridecane, is subjected to a monochlorinationprocess. The alkyl chlorides so obtained are employed in the same manneras isododecylchloride was employed in the previous example, but in anyevent, sufficient oxide is employed to yield a water-soluble surfaceactive product.

Example 4 250 parts of an alkylated cresol mixture, which is. obtainedby causing crude cresol (containing Gil ortho-, metaand paracresol) toreact with the moncchlorination products of a middle oil fracstrengthand condensed with 600 parts of ethylene oxide.

Example 5 7 Example 6 358 parts of a compound of the formula:

wherein R. stands for the acyl radical of oleic acid, are mixed with 3parts of sodium ethylate and the mixture is heated in an iron pressurevessel with 300 parts of ethylene oxide to -100 C.; the temperature ismaintained until the originally existing pressure has disappeared.Thereupon, this treatment is repeated, using each time 300 parts ofethylene oxide until in all 1100 parts of ethylene oxide are absorbed.

Example 7 A product of similar action is obtained, by causing, accordingto one of the methods described in the preceding examples, about 700parts of ethylene oxide to'act upon 2'76 parts'of a compound of theformula CuH22CO.CcH4.0H (undecyl-para-hydroxy-phenyl-ketone) Example 8150 parts of lsobutylphenol are mixed with 15 parts of a solution of 10per cent strength of sodium methylate in methyl alcohol, the mixture isheated to C.- C., and the methyl alcohol is removed under reducedpressure while stirring; thereupon, 260 parts of ethylene oxide areintroduced at C. C., with the absorption of the'oxide.

Example 9 600 parts of crude decylphenol (obtained by condensation ofcrude decyl chloride and phenol) are subjected with addition of 20 partsof caustic soda solution of 46 B. at 120140 C. for about 15 hours toreaction with ethylene oxide gas until 1320 parts of ethylene oxide areabsorbed.

Example 10 Example 11 290 parts of an alkylphenol (which is regarded asconsisting mainly of tetradecylphenol, and is obtainable by firstintroducing 3 parts of boron fluoride into 280 parts of molten phenoland then introducing at 25-30 C. 588 parts of an olefine having aboiling point of 212-21'7 C. and consisting mainly of the hydrocarbonC14H28 and subsequently stirring for about two hours at the sametemperature) are mixed with 2.5 parts of caustic soda solution of 40 B.The whole is heated to 130 C. and 528 parts of ethylene oxide are thenintroduced.

Example 12 Into 288 parts of an alkylphenol, which is ob tained byadding 940 parts ofmolten phenol to polymerizing olefines with six orseven carbon atoms obtainable from the corresponding alcohols in thecatalytic reduction of carbon monoxide.

' Example 13 439 parts of an alkylnaphthoi containing as substituent aradical of about 21 carbon atoms, obtainable by condensing with naphthola trimeric isoheptylene obtained by dehydrating and polymerizing thealcohols produced in the catalytic reduction of carbon monoxide, aremixed with 1 part of powdered caustic potash and the mixture is heatedunder reduced pressure to a temperature of Bil- C., in order toeliminate the water formed. Then 1100 parts of ethylene oxide are,introduced at Mil- 0.

Example 14 206 parts of iso-octylphenol, prepared by condensingdi-isobutylene with phenol in, thepresence of boron fluoride, are mixedwith 0.7 part of powdered caustic soda and heated to 120-130 C. underreduced pressure until the product is anhydrous. 1:2-propylene oxide isthen introduced at a temperature between 160180 C. un-

til 1810 parts have been absorbed.

Example 15 Example 16 V v 182 parts v of p-cyclohexylcyclohexanol aremixed with 1.8 parts 'of caustic soda solution of 40 B. The mixtureisheated to 140-160and 1:2-propy1ene oxide is then introduced until partshave been absorbed. A bright water-insoluble oil is obtained.

In order to render the product soluble in water, 356-parts of the oilypolyether are converted into the alcoholate with the equivalent amountof sodium in xylene. The suspension of the alcoholate is then heated toboiling, while stirring, with 150 parts of sodium chloracetate. Afterremoving the solvent there remains a solid product which contains thesodium salt of the cyclohexyltripropylene glycol hydroxy acetic acid.The oil can also be solubilized by treatment with an additional amountof ethylene oxide.

Example 17 222 parts of iso-octylresorcinol are caused to react,according to one of the above processes, with about 530 parts ofethylene oxide.

Example 18 262 parts of tri-isobutylphenol CLEO-- are treated with 420parts of ethylene oxide according to one of the methods above described.

Example 19 parts of p-caproylphenol-(p-hydroxy-caprophenone) oimonmooOon prepared by condensation of caproic acid chlo- I ride and phenol inthe presence of AlCla, are

dissolved in an alcoholic caustic potash solution containing theequivalent amount of caustic potash, and the whole is caused to reactwith 225 parts of ethylene oxide in the manner pre-- number of arylfatty acids used for various puretc. Reference isalso made to U. S.Patent No. 2

2,144,324, dated January 17, 1939, to Bowles and Kaplan. The procedurethere employed may be used in connection with hydroxybenzyl chloride orthe like.

Another procedure, andin some respects, the simplest procedure for themanufacture of hydroxy aryl fatty acids, is described in U. S. PatentNo. 2,026,217, dated December 31, 1935, to De Groote and Keiser. Inmethods employing a Freidel-Crafts reaction, one is not limited toordinary. fatty acids, but may employ acids such as butyric acid,pentanoic acid, heptoic acid, octanoic acid, decanoic acid, and thelike. Some of these, acids, containing either straight or branchedchains, are obtained by the oxidation of paraflin and are available inthe open market. These acids are generally saturated, but the productsderived by monochlorin'at ion can be reacted with phenolic bodies, oreven with hydroxy hydroaromatic bodies by the Freidel-Crafts or similarreactions, to' give suitable products for subsequent treatment withalkylene oxides, particularly ethylene oxide, in the manner previouslyindicated.

Example 21 1 mole of resorcinol is etherized with 1 mole of octyl oroctadecyl alcohol. The ether thus derived, i. e., the one obtained bymeans of octadecyl alcohol, is treated in the manner previouslyindicated with ethylene oxide to give a suitable water-soluble product.

Example 22 Butylated phenyl phenol is treated in the manner previouslysuggested with ethylene oxide to give a water-soluble product.

Example 23 Phenolic bodies of the kind described in U. S. Patent No.2,086,216, dated July 6, 1937, to De Groote, are employed for treatmentwithan alkylene oxide such as ethylene oxide. Such materials includehexadecyl phenol, palmityl phenol, catyl phenol, capryl phenol, andother phenolic derivatives of waxes having, in some instances, as manyas 32 carbon atoms in the alkyl side chain, or in the acyl radicalattached to the aromatic nucleus. It is to be noted that treatment withethylene oxide need not be limited to any single compound; but if,desired, a mixture of suitable hydroxy hydroaromatics or phenolic bodiesmay be treated. This applies not only to the present example, but to allthe examples previously mentioned and the next succeeding example.

' Example 24 Two moles of amyl phenol are reacted with one mole ofacetone to produce bis-amylphenylol (2,2) propane. The above product istreated with approximately 15-20 moles of ethylene oxide in the mannerpreviously indicated to give a water-soluble surface-active material.

Example 25 Various substituted phenols above described,

particularly alkylated phenols, which are indi-.

equally suitable compounds.

It happens that there are known a iew alicyclic Q derivatives which arein essence analogs of substituted hydroaromatlc alcohols, but instead ofbeing derivatives of cyclohexanol, are derivatives of cyclobutanol andhydro-cycloheptanol, as, for example, 2-octyl-cycloheptanol-1 andcomparable alkylated cyclobutanols. Such materials are water-insolubleand can be solubilized with ethylene oxide or the like so as to resultin surfaceactive material which may be employed in the present process.For the sake of simplicity, it is understood in the hereto attachedclaims that the expression hydroaromatic is employed in its conventionalmeaning, whereas, the expression cyclo-aliphatic is employed in arestricted sense and is intended to include the adjacent cyclic bodiesof the kind just mentioned, to wit,

the derivatives of cyclobutanol and cyclohepta' n01 as well as thehydroaromatic type. In some instances, these compounds appear as minorconstituents in naphthenyl alcohols derived by the reduction of esters,which, in turn, are derived from naphthenic acids which occur naturallyin various crude oils.

Attention is directed to the fact that in certain instances an alkylside chain may in essence be a modification in which there is an oxygenatom attached to a carbon atom as a derivative of a ketone; for example,as a reaction product de rived from phenol and mono-chloropropyl ketone;and one may also note obvious instances in which the hydrocarbon chainis interrupted at least once by an oxygen atom. The introdiic tion of aketone residue, that is, a ketone radical derived hypothetically by theremoval of a hydrogen atom, is in essence an acylalkyl radical, as isreadily apparent from examination of its structure. More broadly, aswhen derived from an aromatic ketone, or an alicyclic or an aralkylketone, (where the hydrogen atom is removed from the alkyl portion) theradical may be considered as an acylhydrocarbon radical. Sometimes suchradicals are referred to as ketonyl compared with acetonyl. However, anarcmatic or hydroaromatic hydroxy compound having a long alkyl chain,even though such alkyl chain is interrupted at least once by an oxygenatom, is still perfectly satisfactory, provided that (a) such phenolicbody or al.0holic body is water-insoluble prior to treatment withalkylene oxide; and (b) it becomes water-soluble upon treatment with analkylene oxide or the equiva lent. It should be noted that although thetreatment with an alkylene oxide or its equivalent is necessary in allinstances to produce water-solubility, yet excessive treatment should beavoided, in that the compound may become extremely hydrophile. Generallyspeaking, it is safe to treat the water-insoluble product with ethyleneoxide so as to increase its weight not less than and not more than 250%,or possibly 300% in some cases. Such procedure is generally asatisfactory guide; and if some other alkylene oxide is employed, forinstance, propylene oxide, then of course an increased amount ofalkylene oxide must be employed, based on the increased molecular weightof propylene oxide and the like, and also based on the fact that itssolubilizing effect per mole is somewhat less than that of ethyleneoxide. If too great an amount of ethylene oxide is used, the resultantcompound loses its surface activity. Generally speaking, 8-15 moles ofthe alkylene oxides or the equivalent per mole of isocyclic compounds,represent an upper limit.

Another convenient guide is that for each carbon atom present in theoriginal water-insoluble material, one must add one-half molecularproportions of the alkylene oxide, if ethylene oxide is used, andpossibly a greater amount if an alkylene oxide of higher molecularweight is employed. An oxide such as benzyl ethylene oxide may beemployed where the original raw material is almost on the verge of beingwater-soluble per se. It also must be remembered that 'the solubility ofthe product obtained varies somewhat with the method of manufacture andthe particular catalyst which is present. It has previously been statedthat this is one of the reasons that the exact composition of thecompounds cannot be indicated as satisfactorily as might be desired inall instances. If solubility is not obtained with any other alkyleneoxide, then ethylene oxide should be employed, because it appears to bebest suited, for the reason that it reacts most readily, and because itpromotes water solubility to a greater degree than other alkylene oxidesor the equivalent. Glycidol, of course, or a similar type of compound isjust as satisfactory as ethylene oxide. In any event,

water solubility can always be obtained, and the range ofsurfaceeactivity is such that there is no difficulty in stopping shortof the point where surface-activity would disappear, due to the presenceof unusually excessive hydrophile properties. Oxygen atoms, if presentin the parent material (in addition to the required hydroxyl radical orradicals) increases water solubility. If the product becomeswater-soluble too easily (1. e., shows insumcient surface-activity)repeat the procedure, but use an alkylene oxide of higher molecularweight.

It may be well to emphasize what has been said previously in regard tosurface-activity of the water-soluble compound. If a dilution of thewater-soluble reaction product of 1 part in 3,000, or 1 part in 5,000,or 20,000, no longer shows any decrease in the surface tension of theresulting solution, as compared with the raw water from which it wasprepared, then one has'obtained a water-soluble product from the parentwaterinsoluble product; but surface-activity has been destroyed, due tothe introduction of an extremely hydrophilic property. Needless to say,suchproduct should be removed and the changes made in the introductionof the alkylene oxide along the lines previously indicated so as toobtain a product that is water-soluble and also surfaceactive. In orderthat it be understood that such extremely hydrophilic compounds are notcontemplated for use in the present process, it will be noted that thehereto appended claims are limited to the surface-active type.

Another point which must beborne in mind is that the products, inaddition to being watersoluble and surface-active, must be resistant tosoluble alkaline earth salts, such as soluble calcium and magnesiumsalts. It sometimes happens that the compound obtained by treatment withthe alkylene oxide is water-soluble and surface-active, but notresistant to calcium and magnesium salts, i. e., the alkaline earthsalts.

even with a sulfonic acid; and such derivatives may be employed. In suchinstances it is to be I equivalent is a non-functional constituent.

noted that the carboxyl group or sulfonic group .is not a functionalgroup in the sense that it particularly adds or detracts from thesolubility of the compound, but may'yield the product which has someother desirable property. Usual- 1y, however, the introduction of anacyl radical will tend to increase the water solubility, but is apt todecrease the resistance to soluble calcium and magnesium salts, unlessthe acyl radical can also be subjected to similar etherization.Similarly, the hydroxyl radical may be removed, if desired, by anetherization process. One reaction which may be employed is concernedwith the use of a material such as methyl sulfate or the like.

Acyl groups, such as sulphonic groups, may beintroduced directly intothe cyclic nucleus. Then again, the presence of a halogen atom orpossibly a sulfonic group, would not be objectionable; but it isunnecessary and as a rule, means only possible increased complexity ofreaction and perhaps an undue added cost. If one desired, one mightstart with a chlorinated phenol; but in this instance also the chlorineatom or its All such conventional variants are well known.

For practical purposes our preference is to use ethylene oxide, ratherthan any other alkylene oxide, because it is cheaper, has lowermolecular weight, and appears to be more reactive. It is also ourpreference to use isocyclic hydroxy compounds free from atoms orradicals of the kind which have just been described. It is alsov ourpreference to obtain water-solubility, surfaceactivity, and resistanceto calcium and magnesium salts, by means of the alkylene oxide only,preferably ethylene oxide or glycidol, and not to obtain theseproperties by the introduction of some radical, such as a carboxylradical or sulfonic acid radical.

Our preferred water-insoluble raw material is a monocyclic phenol inwhich there is present at least one allwl constituent containing atleast six carbon atoms and not more than 18 carbon atoms, such as octylphenol or octadecyl phenol. "It is understood, in view of what has beensaid, that a large class of the materials contemplated may be referredto as glycol, or preferably, polyglycol ethers of water-insolublesubstituted isocyclic hydroxyl compounds of the kind described, i. e.,contain substituted isocyclic nuclei of the kind previously discussed,and which are characterized by also containing the group kylene oxidesmay react with'hydrogen atoms linked to oxygen as in an ordinary highmolecular weight aliphatic alcohol; or such oxides may react with ahydrogen atom linked to an amido or amino nitrogen atom. If such otherreactive hydrogen atoms are present, then in that event it is obviousthat one may obtain a solubilizing.

effect, due in part, to the presence of such other reactive groups. Forsake of simplicity, it is to be noted that compounds so obtained, i. e.,by

virtue of the presence of such other radicals, are contemplated for thesame 'purpose, i. e., the

flooding of subterranean oil sands or strata, in our co-penciingapplications Serial Nos. 322,535

' and 322,536 and filed March 6, 1940.

More specifically then, our preferred flooding agent, treating agent oraddition agent, is prepared by treating a monocyclic alkylated phenolhaving at least one alkyl group, and not more scribed. As a. specificexample of this preferred type, we prefer to treat octyl phenol,preferably having a normal octyl group, although a branched octyl groupor a mixture may be employed, with ethylene oxide until one has'obtainedan increase in weight equivalent to approximately -l75'%.

With the normal octyl phenol, our preference is to use ethylene oxideuntil an increase in weight is approximately In any event, the finishedproduct must be soluble in presence of soluble calcium and magnesiumsalts; and if it is not soluble, a new batch must be prepared employingan increased amount of ethylene oxide, as previously indicated. Comparewith Example labove.

In practising or carrying out our process, the flooding of thesubterranean sands or strata is effected in the conventional'manner,except that in our process the flooding water has added to same, atreating agent or chemical'compound of the kind previously described.The amount of said treating agent or compound added to the floodingwater, is generally relatively small, varying from approximately1-10,000, to approximately 1100,000, and in some instances even less. Insome particular cases, where the Water employed has an extremely highsalinity, and where the oil to be recovered is particularly valuable,one might use a concentration as high as 1-5,000; .but suchconcentration represents an unusual condition and one which would beordinarily uneconomical. In fact, in the majority of cases a ratio of140,000 to 1-80,000 represents a limit which gives both a valuableflooding vehicle and a cost that is economically feasible. As has beenpreviously pointed out, the actual flooding procedure may involve therepeated uses ofthe same flooding }-.vehicle, and after the addition ofthe initial treating agent, it may be necessary to add small amounts ofsaid treating agent from time to time to keep the effectiveness of theflooding vehicle at a predetermined standard of effectiveness.

It is understood that in the hereto appended claims, reference to analkylene oxide broadly or a specific member as ethylene oxide, isintended to include obvious functional equivalents of the kind referredto, to wit, halohydrins, glycidol, epichlorhydrin, and the like. It isalso understood that reference in the appended claims to substitutedisocyclic compounds containing substituents of the kind described may,of course, contain other substituent atoms or radicals, or may containmore than one of the required type of the substituent radical.

Having thus described our invention, what we claim as new and desire tosecure by Letters Patent is:

1. A flooding process for recovering oil from subterranean sands andother oil-bearing strata, which consists in flooding the oleiferousstructure with an aqueous treating solution, comprising a water-soluble,surface-active, alkaline earth-resistant polyglycol ether, which isderived by reacting an alkylene oxide with a member of the classconsisting of water-insoluble substituted aromatic and hydroaromaticcompounds containing at least one hydroxyl radical attached to a nuclearcarbon atom, and a least one nuclear substituent selected from the classconsisting of a hydrocarbon radical containing at least four carbonatoms; a ketonyl radical containing at least four carbon atoms; a satfitufed hydrocarbon radical containing at least four carbon atoms andinterrupted-at least once by an oxygen atom; an acyl radical containingat least four carbon atoms; and an oxy-alkyl radical forming an etherlinkage with a nuclear carbon atom, the alkyl part of such oxy-alkylradical containing at least four carbon atoms.

2. A flooding process for recovering oil from subterranean sands andother oil-bearing strata, which consists in flooding the oleiferousstructure with an aqueous treating solution, comprising a water-soluble,surface-active, alkaline earth-resistant polyglycol ether. which isderived by reacting an alkylene oxide with a water-insoluble substitutedphenol having at least one nuclear substituted alkyl radical containingat least four carbon atoms.

3. A flooding process for recovering oil from subterranean sands andother oil-bearing strata, which consists in flooding the oleiferousstructure with an aqueous treating solution; comprising a sistantpolyglycol ether, which is derived by reacting an alkylene oxide with a,water-insoluble monocyclic phenol having at least one nuclearsubstituted alkyl radical containing at least six carbon atoms.

4. A flooding process for recovering oil from subterranean sands andother oil-bearing strata, which consists in flooding the oleiferousstructure with an aqueous treating solution, comprising a water-soluble,surface-active, alkaline earth-resistant polyglycol ether, which isderived by reacting an alkylene oxide with a water-insoluble monocyclicphenol having at least one nuclear substituted alkyl radical containingat least six carbon atoms and not more than -18 carbon atoms.

5. A flooding process for recovering oil from subterranean sands andother oil-bearing strata, which consists in flooding the oleiferousstructure with an aqueous treating solution, comprising a water-soluble,surface-active, alkaline earth-resistant polyglycol ether, which isderived by reacting an alkylene oxide having at least two car-.

bon atoms and not less than four carbon atoms, with a water-insolublemonocyclic phenol having at least one nuclear substituted alkyl radicalcontaining at least six carbon atoms and not more than 18 carbon atoms.

6. A flooding process for recovering oil from subterranean sands andother oil-bearing strata, which consists in flooding the oleiferousstructure with an aqueous treating solution, comprising a water-soluble,surface-active, alkaline earth-resistant polyglycol ether, which isderived by, reacting ethylene oxide with a water-insoluble monocyclicphenol having at least one nuclear substituted alkyl radical containingat least six carbon atoms and not more than 18 carbon atoms.

7. A flooding process for recovering oil from subterranean sands andother oil-bearing" strata, which consists in flooding the oleiferousstructure with an aqueous treating solution, comprising a water-soluble,surface-active, alkaline earth-resistant polyglycol ether, which isderivedby reacting ethylene oxide with a water-insoluble monocyclicphenol having at least one nuclear substituted alkyl radical containingat least six carbon atoms and not more than 18 carbon atoms; and saidether being further characterized by the factthat the increase inweightobtained by reaction of ethylene oxide with the'phenolic body is withinthe range of 80% to 150%, based on the original weight of the phenolicbody.

8. A flooding process for recovering oil from subterranean sands andother oil-bearing strata, which consists in flooding the oleiferousstructure with an aqueous treating solution, comprising a water-soluble,surface-active, alkaline earth-resistant poiyglycol ether, which isderived by reacting ethylene oxide with a water-insoluble monocyclicphenol having at least one nuclear substituted alkyl radical containingat least six carbon atoms and not more than 8 carbon atoms; and saidether being further characterized by the fact that the increase inweight obtained by reaction of ethylene oxide with the phenolic body iswithin the range of 80% to 150%, based on the original weight of thephenolic body.

9.. A flooding process for recovering oil .from subterranean sands andother oil-bearing strata, which consists in flooding the oleiferousstructure with an aqueous treating solution, comprising a water-soluble,surface-active, alkaline earth-rewater-soluble, surface-active, alkalineearth-resistant polyglycol ether,'which is derived by reacting ethyleneoxide with a water-insoluble monocyclic phenol having at least onenuclear substituted alkyl radical containing at least six carbon atomsand not more than eight carbon atoms; and said ethen being furthercharacterized by the fact that the increase in weight obtained byreaction of ethylene oxide with the phenolic body is within the range of80% to 150%, based on the original weight 'of the phenolic body; saidincrease being obtained by the introduction of at least three and notmore than six moles of ethylene oxide for each mole of phenolic rawmaterial. I

10. A flooding process for recovering oil from subterranean sands andother oil-bearing strata, which consists in flooding the oleiferousstructure with an aqueous treating solution, comprising a water-soluble,surface-active, alkaline earth-resistant polyglycol ether, which isderived by reacting ethylene oxide with octyl phenol so as to introduceat least three moles of'ethylene oxide and not more than five moles ofethylene oxide for each mole of phenolic raw material employed. m

MELVIN DE GROOTE. IBERNHARD KEISER.

